Field
Exemplary embodiments relate to a mesh-type electrode pattern, a formation method of an electrode pattern, and a touch panel including an electrode pattern.
Discussion of the Background
An electronic device, such as a liquid crystal display (LCD), an organic light emitting diode (OLED) display, and an electrophoretic display, may include a touch sensing function so that a user may interact with the electronic device. A touch sensing function may determine whether a user's finger, stylus, etc., touches a screen and touch position information thereof, by sensing a change of pressure, light, etc., which may occur on the screen of the display device when the user's finger or a stylus contacts the screen to write a character or draw a picture.
The touch sensing function of the electronic devices may be realized through a touch sensor. The touch sensor may be classified into various types, such as a resistive type, a capacitive type, an electro-magnetic (EM) type, and an optical type.
In the capacitive type, a capacitive touch sensor may include a sensing capacitor formed by a sensing electrode. The sensing electrode may sense a change in capacitance of the sensing capacitor and transfer a sensing signal when a conductor such as a finger approaches the touch sensor so as to determine existence of a touch, a touch position, and the like. The capacitive touch sensor may include touch electrodes disposed in a touch sensing region and touch wires connected to the touch electrodes. The touch wires may transmit a sensing input signal to the touch electrode and transmit a sensing output signal of the touch electrode, which may be generated depending on the touch, to a touch driver.
The touch sensor may be installed in a display device (an in-cell type), formed on an outer surface of a display device (an on-cell type), or attached on a separate touch sensor panel that may be attached to a display device (an add-on cell type). The panel in which the touch sensor is formed may be referred as a touch panel.
When manufacturing an electronic device such as the touch panel, a glass substrate may be used. Due to heavy and fragile nature of the glass substrate, portability thereof may be lowered, and implementation of the electronic device in a large-size screen display may be difficult. Accordingly, a flexible electronic device, which may be light, withstand impact, and utilizes a plastic substrate having a high flexibility such as polyamide (PI), is being actively researched. In the flexible electronic device, a flexible touch sensor device may include a portion that may be bendable, foldable, rollable, stretchable in at least one direction, or elastic and transformable. Accordingly, an electrode pattern included in the flexible electronic device may include a conductive material having flexibility. For example, the electrode pattern may include at least one of a metal nanowire, a conductive polymer such as poly(3,4-ethylenedioxythiophene) (PEDOT), a metal mesh, a carbon nanotube (CNT), and a conductive material, such as a thin metal layer. The electrode pattern may have a predetermined transmittance to transmit light.
The electrode pattern included in the electronic device, such as the touch sensor, may be a mesh-type, which may have a regular or irregular arrangement. In case of a regularly arranged mesh-type, since the mesh-type has a predetermined space frequency component, when the electrode pattern is attached to the display device, directly formed in the display device, or adhered outside the display device to be folded on the display device, the mesh-type may generate a moiré phenomenon along with other periodic patterns (e.g., a black matrix) included in the display device, which may deteriorate visibility therein. In case of an irregularly arranged mesh-type, a size of a polygon formed by the electrode pattern, that is, the size of an opening, may not be uniform throughout the electrode pattern, such that luminance of light passing through a layer in which the electrode pattern is formed may not be uniform on some regions thereof, such that a dark spot may be recognized by a user.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the inventive concept, and, therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.